Calculating device



J. G. ZOLLMAN CALCULATING DEVI CE Filed July 23, 1923 2 Shoots-Sheet 1 mag ' ATTORNEYS Jan. 20, 5- v 1,523,680

J. G. ZOLLHAN CALCULATING DEVICE Filed July 23, 1923 2 Shunt-Sheet 2 hawv.

A HOB/I578 Patented Jan. 20, 1925.

UNITED STATES PATENT OFFICE.

JOHN G. ZOLLMAN, OF CHICAGO, ILLINOIS.

CALCULATING DEVICE.

Application filed July 23,

To all whom it mag/ concern:

Be it known that I, JOHN G. ZOLLMAN, a citizen of the United States, and a resident of Chicago, in the county of Cool; and State of Illinois,-have invented a new and useful Improvement in Calculating Devices, of which the following, is a full, clear, and exact description. 2

My invention relates to improvements in calculating devices, and it consists in the combinations, constructions, and arrangements herein described and claimed.

An object of my invention is to provide a calculating device which isextremely simple in construction, that is capable of performing a multiplicity of mathematical problems and in a relatively short time.

A further object of my invention is to provide a device of the character described in which the dials upon which the scales are imprinted are removable so that new dials having scales of different values may be substituted therefor.

A further object of my invention is to rovide a device of the character described in which a novel means is employed for mechanically establishing a rotative connection between two cooperating dials.

Other objects and advantages will appear in the following specification, and the novel features of the invention will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawings, forming part of this application, in which Figure 1 is a top-plan view of an embodiment of my invention,

Figure 2 is a side elevation of the mecha nism illustrated in Figure 1, partly in section,

Figure 3 is a view along the line 3-3 of Figure. 2, and

Figure 4 is asectional view along the line 44 of Figure 1 In carrying out m invention, I make use of a substantially at' rigid base 1. The base 1. is provided with an upri ht pin 2 ri idly secured thereto and a tubu ar sleeve 3F1kewise extending upwardly from the base 1 and at a spaced distance from the pin 2.

A pair of rigid fiber scroll gears 4 and 5 are rotatably mounted upon the pin 2 and the sleeve 3 respectively. These gears are in mesh with one another.

A dial 6, which I choose to call the num ber dial, is fixed to the gear 4 in the manner 1923. Serial No. 653,329.

shown in Figure 2 and is concentric with the pin 2. This number dial is provided with legends on its upper face arranged in concentricrings encompassing the entirecircumference of the dial. The first ring is calibrated in'numbers from 10 to 100, as indicated at 7. The second and third rings 8 and 9 are calibrated in values correspon ing .to the square of predetermined values. The calibrations in the first ring are for the square having values from 10 to 32 and the calibrations in the second ring are for squares having values from 32 to 100. The next three rings 10, 11, and 12, respectively, are calibrated in values relating to cubes, the first-ring being for numbers from 10 to 22, the second ring being for numbers from 22 to 47 and the third ring for numbers from 47 to 100. The next two rings on the inner side of the rings 10, 11, and 12, as indicated at 13 and 14, are for sign values, these rings second ring 14 is calibrated in values from 6 degrees to 90 degrees. The last three rings 16, 17 and 18 are calibrated in values relating to tangents, the first ring being calibrated from 6 degrees to 45 degrees, the second calibrated from 45 degrees to 84 degrees, and the third ring calibrated from 84 degrees to 90 degrees. There are therefore eleven concentric rings on the dials 6, each calibrated in certain values and the character'of the calibrations are indicated.clearly on the index card 15. This card is supported on a supporting member 19 at one end and has an opening 20 therethrough, through which the pin 2 is projected and the o poslte end of the card permitted to project eyond the pin 2 as indicated at 21.f,

A transparent strip 22,. preferably of celluloid or the like, is also secured to'the supporting member 19 atone end and likewise is provided with an opening therethrough for permitting the admittance of the pin 2. This transparent strip has a hair 7 lower end and extending tubular member 27 and relative to the scroll V longitudinally of The sleeve is permitted to exthe upwardly extending tubuthe sleeve.

actly overlie lar sleeve 27 7 tion of its length, as indicated in Figure 4 so that the dial 24 may be rotated upon the gear 5. Means for securely fixing the dial 24 against movement relative to the scroll gear- 5 is provided in a resilient ring 28 disposed about the sleeve 25 and arranged to be 1 manually moved longitudinally of that sleeve, When the ring 28 is in the position shown in. full lines in Figure 4, the scroll gear 5 maybe turned. freely relative to the stationary dial 24, but when the resilient 7 ring 28 is disposed in-the position shown in "29, 30, and 31- imprinted. adjacent the peripheraledge 33 other"ini thefsame manner as the legend,

dotted lines, then the dial 24must turn with the scrolli'gear-5. a

The dial 24 is'provided with three rings thereof, one within the rings of the, dial fj. The first ring 29 has legends" thereon representing the log values of the numbers on the numberring 7 on the 1 ing movement of one gear about its center will cause an angular rotatlng movement of the other gear proportional to the log value of thenumber indicated on the first dial. a i

From

the foregoing description of the various parts of the device,-the operation thereof may be readilyunderstood. Let us; i assume thatit is desired to find the-log" the ring 7..of,the dial 6. If this number .is let Ens-say 100 or 10, asshown in Figure 1, the dialis moved until 100 is directly under thehair line 23. The log value of 1 is zero, as indicated on the dial 24 by the legends 29. t

Let us assume that it is desired tosolve.

a problem in multiplication as for commonfractions and proportions. 'In-this'event it is necessary to place the denominator on the number dial on the. scale 1 (see index 15) directly under the hair line 23. f The resilient ring 28 is moved to the position shown in'full lines in Figure 4and the dial 24 is manually rotated relative to the scroll gear 5' until. the third term of theproblem is on the black log scale, i. e., the dial 30. Y a r 4 The resilient ring 25 is then moved to the secured to the gear5 for a porvalue of anyof thefparticular numbers "onon the scale 3 position shown in dotted lines in Figure 4 so that the dial 24 will move with the gear and the upper dial 6 is rotated so that the numerator at this time on the scale 7 falls under the hair line of the problem will appear directly under the hairline 23 upon the dial 2.4 of the blacklog scale. The word black is used to distinguish the scale 30 from the scale 31. The inverted scale which; is in the ring 31"is printed in' red ink and referred to as, the red log scale. The legends onthe ring 29 .are merely log Values and not results calculated on the scales 30 and 31. To solve a problem in'division, it is necessary to turn the number dial until the divisor readable on the scale 7 is directly under the'hair line 23. The dividend, readable upon the black log scale or the scale 30, is thenplaced'under the hair line 23 .and the number dial is :then rotated (at this time the ring 28" must be in the p osi tionshown in dotted lines i-nFigure 4) so that "10 appears under theline'23 on the scale 7.v The quotient is readable directly under'the hair line 23 on the scale 30. i

To solve problems in squares and cubes and-the reverse, their roots, the scales 2 to 6 are employed. Let us assume that it is desired to figure the area of a surface of a sphere having a radius of (ST-inches. The

number dial is set on the scale 1 so that 10 is under the hairline 23. The, dial 24 is then moved so that the'reading 4 pi on the scale 30 is under thehair line. The number dial is then moved (With the resili ent ring 28 in the position shown in dotted lines) until 67. appears on scale No. 3 di rectly under the line 23. The answer, that is the area of the surface of the sphere, is

read'on the black log'scale directly under the hair line. 7 V

I Problemsfrequiring sines or tangents are read afterthe following fashion. Let us saythat itis desired to find the area of, a triangle, two of the sides being given as follows. A equals 26, B equals 43, and'sine C equals 47 degrees and35. It is known that'multiplying by a number is equivalent to dividing by its reciprocal. We may take 3.846, the reciprocal of 26, (calculate it ,by use ofthe scale 31) and place this num- .ber on the scale 1 of the dial Gunder the hair linen23;- We then move the dial 24 so that 43- appearsunder the hair line 23 0. The

the line 23 found tobe I claimz (see scale 8). I The answer is 836.5 on'scale 31.

1. A calculating deviceof the character described comprising .a' pair of 'rotatably mounted dials having legends thereon representing mathematical values and calculation, a pair of scroll gears, one for each of The fourth term p 7 number dial is then. turned until 38 degrees and 41' is'junder said dials, arranged to turn with said dials, said scroll gears being in mesh with one another, the ratio of said gears relative to one another being such as to cause the rotation of one dial when the opposite dial is turned, said scroll gears having such relatively varying radii that any given angular rotating movement of one gear about its center and the consequent movement of its dial will cause an angular rotating movement of the other gear proportional to the log value of a predetermined number indica ed on the first named dial.

2. A calculating device of the character JOHN G. ZOLLMAN. 

